In the heart of the city, this is a 275 feet tall rock structure, also called as PillaiyarKovil. This structure is one of the oldest and calculated close to a million years old. TheCave temple cut out at the pinnacle is believed to have been built in 580 AD. The Temples of Lord Siva called Thayumanava Swami temple, where the lingam is said to be a projection of the rock itself and Lord Vinayagr (uchhipillaiyar) is the attraction of this Rock Fort. There are inscriptions in these temples that date back to 3rd Century B.C. At the foothills of the Rock Fort is a big and beautiful tank and a pavilion where the annual Float Festival enthralls thousands of people.